This document provides questions and answers related to coordination compounds and d-block elements. It contains multiple choice questions testing knowledge of topics like: - Coordination complexes and their IUPAC names - Oxidation states of transition metals and lanthanides/actinides - Factors determining geometry and magnetic properties of complexes - Isomerism in coordination compounds The questions cover concepts essential for understanding the chemistry of transition metals and coordination compounds.

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7. Ans.(2)Bond between C atom of organic molecule and metal atom.

8. 4.Most common oxidation states of Ce (cerium) are (2002)
(1)+2, + 3 2) +2, + 4
3) +3, + 4 4) +3, +5

10. 5.Arrange Ce+3, La+3, Pm+3 and Yb+3 in increasing order of their ionic radii (2002)
(1)Yb+3 < Pm+3 < Ce+3 < La+3
(2)Ce+3 < Yb+3 < Pm+3 < La+3
(3)Yb+3 < Pm+3 < La+3 < Ce+3
(4)Pm+3 < La+3 < Ce+3 < Yb+3

11. Ans.(1)

12. 7.Ammonia forms the complex ion [Cu(NH3)4]2+with copper ions in alkaline solutions but not in acidic
solutions. What is the reason for it ? (2003)
(1)In acidic solutions protons coordinate with ammonia molecules forming NH4 ions and NH3 molecules
are not available
(2)In alkaline solutions insoluble Cu(OH)2 is precipitated which is soluble in excess of any alkali.
(3)Copper hydroxide is an amphoteric substance
(4)In acidic solutions hydration protects copper ions

13. Ans.(1) Cu2+ forms complex with free NHy (4)

14. 8.One mole of the complex compound Co(NH3)5C13, gives 3 moles of ions on dissolution in
water. One mole of the same complex reacts with two moles of AgN03 solution to yield two
moles of AgCl(s). The structure of the complex is (2003)
(1)[Co(NH3)3Cl3].2NH3
(2)[Co(NH3)4C12]C1.NH3
(3)[Co(NH3)4C1]C12.NH3 4) [Co(NH3)5C1]C12

16. 9.In the coordination compound, K4[Ni(CN)4], the oxidation
state of nickel is (2003)
1)0 2) + 1 3) + 2 4) – l

18. A reduction in atomic size with increase in atomic number is a
characteristic of elements of (2003)
(1)d-block 2) f-block
3) radioactive series 4) high atomic masses

19. Ans.(2) f-block elements show a regular decrease in atomic size due to
lanthanide/actinide contraction.

20. The coordination number of central metal atom in a complex is determined by (2004)
(1)The number of ligands around a metal ion bonded by sigma bonds
(2)The number of only anionic ligands bonded to the metal ion
(3)The number of ligands around a metal ion bonded by sigma and pi- bonds both
(4)The number of ligands around a metal ion bonded by pi-bonds

21. Ans - 1 Coordination Number is 2^0 valency

22. Which one of the following complexes in an outer orbital complex ? (2004)
(1)[Fe(CN)6]4– 2) [Ni(NH3)6]2+
3) [Co(NH3)6]3+ 4) [Mn(CN)6]4_

24. Coordination compound have great importance in biological systems. In this context which of the following
statements is incorrect ? (2004)
‘ 1) Chlorophylls are green pigments in plants and contains calcium
(2)Carboxypeptidase – A is an enzyme and contains zinc
(3)Cyanocobalamin is B12 and contains cobalt
(4)Haemoglobin is the red pigment of blood and contains iron

25. Ans.(3)Chlorophyll contains magnesium instead of calcium.

26. Cerium(Z=58)is an important member of the lanthanoids. Which of the following statements about cerium
is incorrect ? (2004)
(1)The common oxidation states of cerium are +3 and +4
(2)Cerium (IV) acts as an oxidizing agent
(3)The +4 oxidation state of cerium is not knownin solutions .
(4)The +3 oxidation state of cerium is more stable than the +4 oxidation state

27. Ans.(3) Oxidation potential of Ce(IV) in aqueous solution is supposed to be -ve i.e. -
0.784 V at 25°C.

28. Which one the following has largest number of isomers? (R-= alkyl group, en =
ethylenediamine) (2004)
1) [Ru(NH3)4C12+] 2) [Co(en)2Cl2]+
3) [Ir(PR3)2 H(CO)]2+ 4) [Co(NH3)5C1]2+

29. Ans.(2)Geomerical and optical isomerisum.

30. The correct order of magnetic moments (spin only values in B.M.) among is (2004)
(1)[MnClJ2- > [CoCl4]-2 > [Fe(CN)6r
(2)[Fe(CN)6]’4 > [CoClJ2– > [MnClJ2-
(3)[Fe(CN)J4- > [MnClJ2– > [CoClJ2-
(4)[MnClJ2- > [Fe(CN)J4– > [CoClJ2-

31. Ans.(1) Number of unpaired e” in Mn2+ is 5, Co2+ is 3 and Fe2+ is zero.

32. The oxidation state of Cr in the complex[Cr(NH3)4Cl2]+ is (2005)
(1)+3 2) +2 3) +1 4)0

34. Calomel (Hg2Cl2) on reaction with ammonium hydroxide gives (2005)
(1)HgNH2Cl 2) NH2-Hg-Hg-Cl
3) Hg20 4) HgO

35. Ans.(1) Reaction between calomel and ammonia is Hg2Cl2 + 2NH4OH -
>Hg + Hg(NH2 )C1 + 2H2

36. The IUPAC name of the coordination compound K3[Fe(CN)6] is (2005)
(1)Potassium hexacyanoferrate (II)
(2)Potassium hexacyanoferrate (III)
(3)Potassium hexacyanoiron (II)
(4)tripotassium hexcyanoiron (II)

37. Ans.(2) Complex of Fe3+ is ferrate(III).

38. Which of the following compounds shows optical isomerism? (2005)
1) [Cu(NH3)4]+2 2) [ZnCl]-2
3) [Cr(C204)3]-3 4) [Co(CN)6]-3

40. The value of the ‘spin only’ magnetic moment for one of the following configurations is
2.84 BM. The correct one is (2005)
(1)d4 (in strong ligand filed)
(2)d4 (in weak ligand field)
(3)d3 (in weak as well as in strong fields)
(4)d5 (in strong ligand field)

42. The IUPAC name for the complex [Co(N02)(NH3)5]C12 is (2006)
(1)nitrito-N-pentaamminecobalt (III) chloride
(2)nitrito-N-pentaamminecobalt (II) chloride
(3)pentaammine nitrito-N-cobalt (II) chloride
(4)pentaammine nitrito-N-cobalt (III) chloride

43. ANS - 4 Naming of ligand is in order NH3 and NO2-

44. Nickel (Z = 28) combines with a uninegative monodentate ligand X~ to form a
paramagnetic complex [NiXJ2-. The number of unpaired electron(s) in the nickel and
geometry of this complex ion are, respectively (2006)
(1)one, tetrahedral 2) two, tetrahedral
3) one, square planar 4) two, square planar

46. In Fe(CO)5, the Fe-C bond possesses (2006)
(1)k -character only
(2)both 0 and n characters
(3)ionic character 4) a -character only…

47. Ans.(2) Because of back bonding both o and k bonds are present.

48. How many EDTA (ethylenediaminetetraacetic acid) molecules are required
to make an octahedral complex with a Ca2+ ion ? (2006)
(1)Six 2) Three 3) One 4) Two

49. Ans.(3) EDTA4- is hexadentate ligand.

50. Lanthanoid contraction is caused due to (2006)
(1)The appreciable shielding on outer electrons by 4f electrons from the nuclear charge
(2)The appreciable shielding on outer electrons by 5d electrons from the nuclear charge
(3)The same effective nuclear charge from Ce to Lu
(4)The imperfect shielding on outer electrons by 4f electrons from the nuclear charge

51. Ans.(4) Poor slidding by f-electrons.

52. The actinoids exhibits more number of oxidation states in general than the lanthanoids.
This is because (2007)
(1)The 5f orbitals are more buried than the 4f orbitals
(2)There is a similarity between 4f and 5f orbitals in their angular part of the wave function
(3)The actinoids are more reactive than the lanthanoids
(4)The 5f orbitals extend further from the nucleus than the 4f orbitals

53. Ans.(4) The actinoids exhibit more number of oxidation states in general than the
lanthanoids. This is because the 5f orbitals extend further from the nucleus than the 4f
orbitals.

54. The coordination number and the oxidation state of the element ‘E’ in the
complex [E(en)2(C204)]N02(where ‘en’ is ethylene diamine) are,
respectively, (2008)
1) 6 and 2 2) 4 and 2
3) 4 and 3 4) 6 and 3

56. Larger number of oxidation states are exhibited by the actinoids than those by the
lanthanoids, the main reason being (2008)
(1)4f orbitals more diffused than the 5f orbitals
(2)Lesser energy difference between 5f and 6d than between 4f and 5d orbitals
(3)More energy difference between 5f and 6d than between 4f and 5d orbitals
(4)More reactive nature of the actinoids than the lanthanoids

57. Ans.(2) Being lesser energy difference between 5f and 6d than 4f and 5d orbitals.

58. Knowing that the chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state,
which of the following statements in incorrect?(2009)
(1)Because of the large size of the Ln(III) ions the bonding in its compounds is
predominantly ionic in character
(2)The ionic sizes of Ln(III) decreases in general with increasing atomic number
(3)Ln(III) compounds are generally colourless
(4)Ln(III) hydroxides are mainly basic in character

59. Ans.(3) Ln+3 compounds are mostly coloured.

60. Which of the following has an optical isomer?(2009)
1) [C0(NH3)3C1] 2) [CO(en) (NH3)2]2+
3) [C0(H20)4(en)]3+ 4) [CO(en)2(NH3)2]3+

61. Ans.(4) It is an octahedral complex of the type [M(AA)2X2] where AA is bidentate
ligand.

62. In context with the transition elements, which of the following statements is incorrect ?(2009)
(1)In addition to the normal oxidation states, the zero oxidation state is also shown by these
elements in complexes
(2)In the highest oxidation states, the transition metal show basic character and form cationic
complexes.
(3)In the highest oxidation states of the first five transition elements (Sc to Mn), all the 4s and 3d
electrons are used for bonding.
(4)Once the d3 configuration is exceeded, the tendency to involve all the 3d electrons in bonding
decreases.

63. Ans.(2) In higher oxidation states transition elements show acidic nature.

64. Which of the following pairs represents linkage isomers ? (2009)
(1)[Cu (NHj )4 ][PtCl4 ] and [Pt(NH,)4][CuCl4]
(2)[Pd (PPh3 )2 (NCS)2 ] and[Pd(PPh3)2(SCN)2]
(3)[CO(NH3)5N03]S04and [co(NH3)5S04]N03
(4)[PtCl2(NH3)4]Br2 and [PtBr2 (NH3)4]C12

66. Which of the following complex species is not expected to exhibit optical
isomerism ? (2013)
1) [Co(en)3]3+ 2) [Co(en)2C/2]+
3) [Co(NH3)C/3] 4) [Co(en)(NH3)2C/2]+

67. Ans.(3) [Co(NH3)3C/3] do not exhibit optical isomers but othee exhibit.